The methods of working such materials (molding, cutting, thermoforming . . . ) are well-known and the invention is directed to the topologic structure of the shape of the manufactured products, which gives said products a remarkable transformability by means of an extremely easy manipulation.
GB-A-2 215 226 discloses a bag-like toy adapted to be reversed thereby to exhibit one or the other of its faces outside. Each face can have a desired shape.
The educational and play interest of such an object is limited to the arbitrary shapes of the bag-faces, because reversal of a bag is not amazing per se.
Moreover, GB-A-2 214 093 discloses a game made of cubes articulated to each other along coplanar axes, thereby to be rendered unloosable. This game has no particular effect with respect to volume variation.